Gagne, who spent his first 10 NHL seasons with the Flyers, was acquired from the Kings on Tuesday in exchange for a 2013 fourth-round draft pick. He took an overnight flight from Los Angeles, landing not long after sunrise, and said he tried to get as much sleep as he could before the game. He was welcomed back with a tribute video and a number of loud ovations.

Later, he thanked the crowd the best way possible – by scoring his first goal in more than 15 months.

"I almost feel like I never left," said Gagne, who gave the Flyers a 3-0 lead via the power play early in the second period. "Just walking in the building before the game, knowing everyone, everybody is still here. And a nice welcome I got in the warm-up and after the first five minutes in the period, stuff like that. It's almost like coming back home. I was here for 11 years, everything started here. Definitely fun and it definitely helped me tonight to get through the tough travel yesterday, definitely helped me to get through the game and feeling good."

Joel Ward scored the Capitals' lone goal. Goalie Braden Holtby, who stopped all 33 shots he faced in Washington's 3-0 win against Carolina on Tuesday, was pulled in the second period after allowing four goals on 18 shots.

The extra boost showed itself in the game's first minute, as Giroux scored his seventh goal of the season just 23 seconds into the game. Scott Hartnell, who had a pair of assists, fired a shot from the left side that Holtby stopped, with the rebound going behind the Washington net. Hartnell chased after it and poked it away from the Caps' Mike Green, and then from his knees backhanded a pass off Karl Alzner's skates to Giroux, who was unmarked in the left slot. The goal also extended Giroux's point-scoring streak to six games, including three in a row with at least two points.

It also marked the first time in five games the Flyers had scored the game's first goal, and snapped the Capitals' streak of eight straight scoring the game's first goal.

"We talked about it for the last couple days," Hartnell said. "We wanted to have a great start, continue that through 60 minutes. It was as close as you're going to get for a full 60 minutes."

Part of the Flyers' strong effort can be credited to playing a tired team in the Capitals, who were skating on back-to-back nights and for the fourth time in seven days.

"We've been in those shoes before," Flyers coach Peter Laviolette said. "Sometimes everybody's intentions are good, but you're trying to get oil out of a rock. Washington came here and kept playing to the end, but it's difficult. They played probably an emotional game against Carolina [Tuesday], a really good game, had to travel through the night and they catch a fresh team. We've been in those shoes; they're not easy shoes to walk in."

Capitals coach Adam Oates admitted his team looked tired.

"I think it was all of us and we looked a little tired," he said. "We didn't have enough fight to fight back through them. I think it's a little bit of the product with the League right now because of the lockout with scheduling. Teams are tired. … We look like as a man, no one really had any jump."

His players agreed that exhaustion, at least on the mental side, was part of the problem Wednesday.

"It looked like that at least mentally [tired], in my opinion," Alzner said. "Weren't executing on the plays that we have been in the past few games, and it just wasn't a good effort by us."

After the Flyers made it 2-0 on Simmonds' power-play goal, the Flyers got another jolt of energy from Gagne. Late in a Philadelphia power play, Briere passed the puck from behind the net to Brayden Schenn. Schenn fought off Joey Crabb in the slot and backhanded a pass to Gagne, who scored his first goal since Nov. 17, 2011, when he was with the Los Angeles Kings.

Gagne played with nine players on the current roster, and having him back in the dressing room certainly provided a lift.

"Seeing him for the first time coming to the rink a little after 4 p.m. was pretty cool," Hartnell said. "I think he obviously feels comfortable. He played here 10-plus years. He definitely adds a lot more excitement to the dressing room and it showed right from the get-go."

"Big lift," added Talbot. "He's a guy that's well-known here, well-loved. He brought a loft of energy, passion to the game, he was making plays out there. He gave us good momentum."

Talbot provided his own momentum when he scored his first goal of the season at 14:55 of the second to make it 4-0. Mike Ribeiro cleared the puck out of the Washington zone right to Bruno Gervais in the neutral zone. He moved it across to Luke Schenn while the Flyers' forwards cleared the zone. Schenn then sent the puck to Talbot, who took two strides over the blue line, wound up and fired a slap shot that went off Holtby's glove on its way into the net.

Phillip Grubauer, called up from Hershey of the American Hockey League earlier Wednesday with Michal Neuvirth sick, made his National Hockey League debut when he replaced Holtby after Talbot's goal. He stopped all 14 shots he faced.

“He's played great for us, get him out of there," Oates said of Holtby. "Plus the fourth goal, he looked like he should have had it, and just like everybody he has to take his lumps, too. He's got to bounce back for Winnipeg (Saturday night)."

Ilya Bryzgalov, who finished with 23 saves, had his attempt at a shutout ended with 2:09 left in the third. Jay Beagle beat Ruslan Fedotenko on a faceoff in the Philadelphia end, drawing the puck back to Tom Poti. Bryzgalov stopped his shot from the right point, but the puck bounced off his chest and before he could control it, Ward tipped it away from him and scored.